AIPMT PRELIMS2009Physics-Electromagnetic Induction

AIPMT PRELIMS 2009 Physics Faraday's Law MCQ Question

Type: MCQ-numerical-Hard-Class 12

A conducting circular loop is placed in a uniform magnetic field 0.04 T with its plane perpendicular to the magnetic field. The radius of the loop starts shrinking at 2 mm/s. The induced emf in the loop when the radius is 2 cm is:

A

4.8 π μV

B

0.8 π μV

C

1.6 π μV

D

3.2 π μV

Correct Answer

Option D

Detailed Explanation

The induced emf (ε) is given by ε = -dΦ/dt, where Φ is the magnetic flux. Φ = B × πr². Differentiating with respect to time, ε = -B × 2πr × (dr/dt). Substituting B = 0.04 T, r = 0.02 m, dr/dt = -0.002 m/s, ε = 1.6 π μV.

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